Circuit interrupter



Jan. 6, 1942.

H. H. FAHNOE CIRCUIT INTERRUPTER 2 Sheets-Sheet 2 Filed Deo. 21, 1939 4 LE 0T Z wm M v m @a y lNVENToR /ara/d )SZ/[7270 e.

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m7 ,MLUCUW Patented Jan. 6,1942v 2,269,339 CIRCUIT INTERRUPTER Harold H. Fahnoe, Wilkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 21, 1939, Serial No. 310,395

(Cl. '20o- 120) 21 Claims.

My invention relates, in general, to electric circuit interrupting devices, and, more particuy larly, to means for extinguishing arcs formed by operation of such vdevices to interrupt a circuit.

Although my invention will be disclosed as incorporated in a high voltage fuse wherein it has certain particular novel cooperation to acchieve corresponding new and improved re sults, it will be apparent that my invention is also applicableito other types of circuit interrupters or devices wherein it is desired to extinguish an electric arc.

It has been found that in the so-called selfgenerated gas blast type of interrupter, where an arc is drawn in a passage having ,walls of a material which is capable of evolving relatively large quantities of un-ionized gas when in proximity to an electric arc, that to effectively lextinguish arcs of different current magnitudes, arc 'passages of .different sizes should be employed. It has been found that small current arcs are more effectively extinguished in small bore passages, and that larger current arcs require passages of correspondingly larger bore. Therefore, it is `not only desirable to provide are. passages of difterent sizes for interrupters -of different current ratings, but it is also desirable that arc passages of different sizes be available for extinguishing arcs ofdifferent current values within the range of an interrupter of a given current rating.

Accordingly, it is an object of my invention-to provide an arcextinguishing structure having a plurality of arc' passages of dilierent sizes adapted for use in interrupters of different current ratings.

Another object of my invention is to provide an arc extinguishing structure having an arc passage of a size determined by the current rating of the interrupter, which passage is automatically enlarged upon the striking of an arc in the passage of a predetermined larger current value, to effectively extinguish the same;

Another object of my invention is to provide an arc extinguishing structure having a plurality of arc passages of diierent sizes adapted for use in interrupters of different current ratings, with any one of such passages being capable of automatically enlarging in response to the striking of an arc in the passage greater than a predetermined current value.

An objection to arc extinguishers of the selfgenerated gas blast type is -that on heavy current faults, dangerous gas pressures may be developed and quantities of ionized gases may be .v

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discharged from the fuse holder to the surrounding atmosphere, which may cause flashovers. The pressure developed on such faults may also be sufficient to cause damage to the fuse holder. One way to overcome these defects is by totally enclosing the/ interrupter and providing relatively expensive condenser or baille structure for the evolved gases. One such structure is shown 'in the patent to J. Slepian, No. 2,077,276, issued April 13', 1937, and assigned to the assignee of this invention. y

It is another object of m'y invention to provide an `arc extinguisher of the self-generated gas blast type with deionizing passages for the gases after their passage through the arc and leading to atmosphere.

Another object of my invention is to provide in an arc extinguisher of the self-generated gas blast type, passages having inner wall portions of gas evolving material for conducting gases emanating from the arc to the atmosphere. Another object of my invention is to provide a novel high voltagefuse structure constructed so as to relieve any excess pressure developed therein.

A further object of my invention is to provide a standard high voltage fuse refill element which is adapted for use in fuse holders of different Current ratings. y

A still further object of my invention is to provide a high voltage fuse having arc extinguishing means of the self-generated gas blast typewith novel means fordeionizing such gases before their passage to atmosphere.

lThese and-other objects of my invention Will become more. apparent upon consideration of the following speciiication of preferred embodiments thereof, in Connection with the attached drawings, in which: A

Figure 1 is a longitudinal sectional view showing a high voltage fuse embodying one form of my invention with a part of the fuse shown in elevation;

Fig. 2 lis an enlarged transverse sectional view taken substantially on the line II-II of Fig. 1;

Fig. 3 is a longitudinal sectional view of a 'modified form offuse embodying my invention;

Fig. 4 is a longitudinal sectional view of a slightly modified form of fuse rell unit capable of use with the fuse holder shown in Fig. 3; and

Fig. 5 is a transverse sectional view taken substantially on the line V-V of Fig. 4.

Referring to Figs. 1 and 2 of the drawings, I have shown a fuse holder embodying an outer evolving material 24, and secure the same in vposition to the fuse link 22. 'I'hus the pluralrell unit have not only the function of providing a restricted arc passage, which may automatically be increased in cross section by rupture of the partition walls between the bores in response to an arc drawn in one of the bores,

the current of which is above a predetermined magnitude, but this construction also enables the use of a single type of refill unit including a lining of gas evolving material as standard equipment for or replacement units for, fuses ofa plurality of different current ratings.

In Fig. 3, I have shown another form of fuse holder also including a refill unit. The refill unit in this embodiment of my invention is somewhat similar to that described in connection with Figs. 1 and 2, and, therefore, like reference numerals will be employed to designate like parts.

The fuse holder in this embodiment of my invention includes an insulating fuse tube 32 which may'be of ber, glass or the like, having a terminal ferrule 34 threadedly mounted on the upper end thereof and a terminal ferrule 36 secured to the opposite end thereof in any desired fashion, such as, for example, asvby the indentation 38. .The upper holder ferrule 34 is provided with an internal shoulder 40 on which is seated a terminal cap 42 for the rell unit, with the terminal cap' being-secured against the shoulder by the threaded plug 44 engaging internal threads in the outer'end of the holding ferrule 34.

The refill unit in this embodiment of my invention includes an outervinsulating tube I0, as in the previously described embodiment, provided with a lining 24 of gas-evolving material through which extend a plurality of bores 26, 28 and 30. The refill unit shown in Fig. 3 differs from that previously desoribedin that the end terminal 42 is in the form of a cap, to close off one end of the refill element, and the arc drawing rod I6 is electrically secured to the inner surface of the refill terminal cap 42 by the fusible link 46 and screw 41. The lining 24 of gas-evolving material is maintained in position within the rell tube I by the end insulating washer elements 48 and 58. The Washer element 48 is secured in position by the end refill terminal cap 42, and the insulating washer 58 is secured in position by being threaded into the opposite end of the refill tube I6. .The insulating washers 48 and 50 -are suitably apertured, as shown, to form prolongations of the bores through the gas-evolving material 24. The arc drawing rod I6 is secured to the lower terminal ferrule 36 of the fuse holder by a vflexible shunt 52, secured to the lower end of the arc drawing rod I6, as by thelnuts 56, from where it extends downwardly through an apertured insulatingplug 66 threaded in the lower end ofthe fuse holder, to be secured to the lower terminal ferrule 36 as by a thumb screw 54. A coiled compressie! spring 58 is maintained ina compressed condition between the'insulating washer 58 of the refill unit and the nuts 56 on the arc drawing rod I6.

The operation ofthis embodiment of my invention is much the same as that described in connection with the embodiment shown,I in Figs. 1 and 2, especially as regards the operation of the refill 'unit with particular regard to the operation of the bores through the gas-evolving material 24. Hence'any duplication of operation will be avoided in order not to repeat what has been stated before.

On low current faults, thisI fuse link blows and the arc drawing rod I6 is withdrawn by the compression spring 58 at the bottom or vented end of the fuse holder. The arc is then extinguished in the corresponding hole or bore of the refill unit due to its prolongation and the deionizing.

action of the gas blast produced by decomposition of a portion of the fuse tube lining. Since the smaller bores are used with the lower rated fuse elements, the correspondingly lower fault currents are readily clearedin the smaller bore holes. On heavy fault currents, this fuse operates without the violent explosive action and expulsion of the conducting member I6 typical of pre-y vious types of expulsion fuses where thearc is drawn toward the closed end of the fuse tube, for example, as in the construction shown in Figs. 1 and 2 and in a structure of the type shown in` the previously mentioned Rawlins patent. The action taking place in the fuse shown in Fig. 3 is similar to that described for the lower current interruption except that the greatly increased quantity of gases evolved form the lining material 24, flows generally upwardly in the bore 30 in which the arc is drawn, inasmuch as the arc drawing rod I6 substantially fills the lower portion of rthis bore. These gases will then flow in a reverse direction through the unused bores 28 and26, paralleling the bore in which the arc interruption is taking place. Inasmuch as these gases flowing through the unused bores 26 and 28 may be at a relatively high temperature and may even include flames, additional evolution of un-ionized gases takes place in these bores to insure deionization of the gases before their escape from the fuse holder. parallel paths, of course, is prevented by the evolution of un-ionized gases from thematerial lining these paths.

Thus the gases escaping upwardly through the bore 36 or whichever bore may be used for'circuit interruption, are cooled and deionized before they are permitted to leave the fuse tube. Relatively small quantities of gases mayf escape from the lowei end of the bore in which circuit interruption is taking `place and to aid in cooling and deionizing of these gases, a metallic sleeve 62 may be provided within the .lower portion of the insulating tube 32 between the lower end in sulating plug and the refill element, to present cooling surfaces to these gases to act as a condensing means in the path of all of the gases from the refill element to the exit or lower end of the fuse holder.

In Figs. `5 and"6, I have shown a fuse refill unit which is very similar to that shown in Fig. 3, and hence like reference numerals Iwill be used to designate likeparts. The refill unit shown in Fig. 4 differs from that shown in Fig. 3 only in the provision of` an elongated rell cap 64 to provide a relatively large space within the upper end of the rell unit, as viewed in Fig. 4e for a purpose to be hereinafter'described. One other distinction in this embodiment of my invention resides in the particular form of bores provided through the gas-evolving material 24. As shown in'Fig. 4, and more particularly in Fig. 5, the gasevolving ,'material 24 is provided with a central bore 68 for receiving the arc drawing rod I6, andan cuter annular concentric bore 'II about the inner bore 68. The gas-evolving material 24 is maintained in position in the refill unit by insulatlng washers 12 and 66 as in the previous em- Flashover in these 4 s bodiment of my invention, and these insulating washers are provided with `a circular series of periorations l, and a central perforation for aligning-With the `bores through the gas-evolving material 2t,

The operation of this 'embodiment oi my invention is much the same as that described in connection with Figs. l to 3, with the distinction that by the provision of the elongated refill \.ter. minal cap 6d, I have herein provided a condensing chamber formed'by the walls of the metallic cap SB which is in the path of the gases coming from the bore in which the arc is established, and prior to their passage through the unused bore lo. This interposed condensing cap 65 acts to condense some of the gases before they enter the auxiliary bore 'l0 and thus aids in cooling and aaeaeee CII deionizing the gases prior to their escape from a fuse holder. As in the previous embodiments of my invention, the partition wall between the bores 58 and 'I0 is made thin so that it may be broken upon the development of excessive pressure in the bore in which an arc is drawn. Also, for uses having a high rating, the arc drawing rod i6 may be positioned in the bore 10 rather than in the bore 68, in which event the bore 58 will function as a deionizing passage for the gases prior to their escape to the atmosphere.

From the foregoing, it is apparent that I have provided a novel type of fuse refill unit which embodies a .,p1uralityl of arcrpassagesaof dilierent cross sectional areas adapted for use in fuses of correspondingly different ratings, and which passages also function to enlarge the particular arc passage employed for extinguishing an arc, when currents above a predetermined magnitude are interrupted, and which further function when vemployed in a fuse holder of the type illustrated in Fig. 3 upon the interruption of currents of predetermined values, as deionizing passages for the escaping arc gases prior to escaping to the atmosphere. Also, the fuse and rell units described in connection with Figs. 3 and 4 of the drawings may be provided with additional lcooling and condensing means to further insure that the escaping gases are completely cooled and deionized prior to their release to the atmosphere.

lHaving described preferred embodiment of my invention in accordance with the patent statutes, I desire it to be understood that my invention is not limited to the particular embodiments disclosed hereby, inasmuch as it will be obvious, particularly to persons skilled in the art, that many changes and modifications may be made in these embodiments without departing from the broad scope and spirit of my invention. I desire, therefore, that my invention be interpreted as broadly as ,possible and that it be limited only by what is expressly stated in the following claims.

I claim as my invention:

l. In a circuit interrupting device, an arc structure including at least three ci arc passages of different size, partition means separating said passages, said means being destructible in response to the striking of an arc in an adjacent passage, the current of which is above a predetermined magnitude.

2. In` a `.circuit interrupting device, an arc a predetermined magnitude, and means soley in vone of said passages for striking an arc.

3. In a circuit interrupting device, an arc structure including a solid block. of a material capable of evolving an arc extinguishing gas when in proximity to an electric arc having a plurality of substantially parallel arc passages of different sizes therethrough, and the material of said block separating said passages being de-` -structible in response to the striking of an arc in one of said passages of a predetermined current magniture, and means for striking an arc in one only of said passages.

4. In a circuit interrupting means, an arc structure having substantially parallel circular bores of diierent diameters extending therethrough, with at least the inner wall portions of said bores being of a material which is capable of evolving an yarc extinguishing gas when subjected yto heat, and means for striking an arc in only one of said bores. v

5. In a circuit interrupting means, an arc structure having substantially parallel arc passages of dierent cross sectional arcas extending through the structure, with at least the inner wall portions of said passages being of a material capable of evolving an arc extinguishing gas whenin proximity to an electric arc and means in only one of said passages for striking an arc,

6. In a circuit interruptor, an enclosure having an open end, means in said enclosure forming a restricted 'arc passage communicating at one end thereof with said open end of said enclosure, means for striking an arc in said passage, auxiliary passages in said enclosures for venting the vother end of said arc passage to said open end of said enclosure, at least inner wall portions of said passages being 'of a material capable of evolving an are extinguishing gas when heated, and partition means between said passages which is destructible in response to the striking of an arc in said arc passage above a predetermined current magnitude.v

7. In an interruptor, a tubular enclosure hav- Ving a closed end and an open end, means in said vend of said enclosure with the open end thereof,

structure including a plurality of arc passages and one end of said enclosure presenting relatively large cooling areas to gases passing therethrough to act as a condenser.

8. In a circuit interrupter, a tubular support having a closed end and an open end, a terminal at the closed end thereof, arc extinguishing means in saidsupport and adapted to be secured in-position adjacent said closed end of the support, said arev extinguishing structure embodying an arc passage, at least inner wall portions of which are of a material capable of evolving an arc extinguishing gas when in proximity to an electric arc, means biased to draw an arc through said passage toward the open end of said support, means for automatically interrupting a circuit upon the passage therethrough of currents above a predetermined value for normally maintaining said arc drawing means against movement and connecting said arc drawing means to said terminal, and condensing means in said support located outwardly of said arc extinguishing structure.

9. A fuse refill unit, including a tubular cartridge having a closed end and an open end. means in said cartridge forming a restricted arc passage having inner wall portions of a material capable of evolving an arc extinguishing gas when in proximity to an electric arc, arc drawing means in said passage, resilient means adapted to move said arc drawing means through said passage and out the open end of said cartridge, fusible means for normally restraining such movement, pressure relief passage means through said passage forming means and communicating with said-arc passage adjacent the closed end of said cartridge, and the portions of said passage forming means between said passages being frangible in response to the interruption of currents above predetermined values in said arc passage.

10. A fuse refill .unit including a tubular cartridge having a closed end and an open end, means in said cartridge forming a restricted arc passage having inner wall portions of'a material capable of evolving an arc extinguishing gas when in proximity to an electric arc, arc drawing means in said passage, resilient means adapted to move said arc drawing means through said passage and out the open end of said cartridge, fusible means for normally restraining such movement, an annular pressure relief passage Ithrough said passage forming means, and communicating with said arc passage adjacent the closed end of said cartridge. Y

11. A fuse refill unit including a tubular cartridge of insulating material having a closed end and an open end, means in said cartridge forming a restricted arc passage having inner wall portions of a material capable of evolving an arc extinguishing gas when in proximity to an electric arc, arc drawing means in said passage, resilient means adapted to move said arc drawing means through said pa'ssage toward the open end of said cartridge, fusible means for normally restraining such movement, pressure relief passage means through said passage forming means, and an enlarged condensing header structure of conductingmaterial formed adjacent the closed end of said cartridge and communicating with the adjacent ends of said passages.

12. vIn an arc extinguishing device adapted for and having but a single arc striking means, said structure including a plurality of arc passages of different cross-sectional areas adapted for the safe interruption of currents of said different ratings, respectively, and partition means separating said passages which is destructible in response to the striking of an arc in any one of said passages the current of which is above a predetermined magnitude.

13. In an interrupter, a tubular enclosure of insulating material having a closed end and an open end, means in said enclosure and spaced from the closed end thereof for defining a restricted arc passage, means for striking an arc in said passage, pressure relief means communieating the space at the closed end of said enclosure with the open end thereofand the closed end of said enclosure comprising an elongated tubular cap of good heat conducting material to form condensing means for gases passing through said space atsaid closed end.

14. In a fuse, a tubular fuse holder ofinsulation material having contact means adjacent opposite ends thereof, a rell unit for said holder including a tubular enclosure having an open end and a closed end including terminal means, said unit adapted to -be removably supported in said end of said enclosure adjacent said one end of said holder, and with the terminal means thereof electrically connected to the contact; means at g use in circuit interrupters of different ratings said end of the holder, means of a material capable of evolving an arc extinguishing gasvwhen' in proximity to an electric arc forming a narrow arc passage in said enclosure, means biased to draw an arc along said passage toward the open end of said enclosure, fusible means connecting said terminal means and arc drawing means to normally prevent relative movement thereof, a exible shunt connecting said arc drawing means to the other of said holder contact means, and the other end of said holder being open at least when said fusible means blows.-

l5. In a fuse, a tubular fuse holder of insulation material having contact means adjacent op, posite ends thereof, a refill unit for said holder including a tubular enclosure having an open end and a closed end including terminal means, said unit adapted to be'removably supported insaid holder adjacent one end thereof with the closed end of said enclosure adjacent said one end of said holder, and with the terminal means thereof electrically connected to the contact means at` said end of the holder,fmeans of a material capable of evolving an arc extinguishing gas when in proximity to an electric arc forming a narrow arc passage in said enclosure, means biased to draw an arc along said passage toward the open end of said enclosure, means venting the closed end of said arc passage to'the open end of said enclosure, fusible means connecting said terminal means and arc drawing means to normally-pre vent relative movement thereof, a flexible shunt connecting said arc drawing means to the other of said holder contact means, and the other end of said holder being open at least when said fusible means blows. j

16. In a fuse, a tubular fuse holder of insulation material having contact means adjacent opposite ends thereof, a refill unit for said holder including a tubular enclosure having an open end and a closed end including terminal means, at least inner wall portions of said enclosure at said closed end being of heat conducting material, said rell unit adapted to be removably supported in said holder adjacent one end thereof with the closed end of said enclosure adjacent holder adjacent one end thereof with, the closed said one end of said holder, and with the terminal means thereof electrically connected to the contact means at said end of the holder, means of a material capable of evolving an arc extinguishing gas when in proximity to an electric arc forming a narrow arc passage in said enclosure, means biased to draw an arc Valong said passage toward the open end of said enclosure, means venting the closed end of said arc passage to the open end of said enclosure, fusible means connecting said terminal means and arc drawingmeans to normally prevent relative movement thereof, a flexible shunt connecting said arc drawing means to the other of said holder contact means, and the other end of said holder being open` at least when said fusible mean blows.

17. In a fuse, a tubular fuse holder 0f insulation material having contact means adjacent opposite ends thereof, a refill unit for-said holder including a tubular enclosure having an open end and a closed end including terminal means, said unit adapted to be removably supported in said g holder adjacent one end thereof with the closed end of said enclosure adjacent said one end of said holder, and with the terminal means thereof electricauy connected te the contact at said end of the holder, means of a material capable of evolving an arc extinguishing gas when in proximity to an electric Aarcforming a narrow arc passage in said enclosure, means biased to draw an arcalong said passage toward the open end of said enclosure, means venting the closed end of' said arc passage to the open end of said enclosure, fusible means connecting said terminal,

means and arc drawing means to vnormally prevent relative movement thereof, a flexible shunt connecting said arc drawing means to the other of said holder contacts, the other end of said holder beinghopen at least when said fusible means blows, and inner wall portions of said holder between said refill unit and the open end of said holder being of a heat conducting material so as to condense gases emitted from the open' end of said'rell when said fusible means blows, prior to their escape from said holder.

I8. In a fuse, a ,tubular fuse holder of insulation material having contact means adjacent opposite ends thereof, a rell unit for said holder the adjacent holder contact, said one end of said fuse being closed and the other end thereof being open at least during a circuit interrupting operation, means of a material capable of evolving an arc extinguishing gas when in proximity to an electricarc forming a narrow arc passage in said enclosure, means biased to draw an arc along said passage toward the open end of said fuse, fusible means connecting said terminal means and arc drawing means to normally prevent relative movement thereof, a flem'blevshunt connecting said arc drawing means to the other of said holder contacts, and means venting the closed end of said fuse to the open end thereof, includand including a tubular enclosure having a terminal at one end thereof and adapted to be supported in said holder adjacent one end thereof with said`terminal electrically connected with the adjacent holder contact, said one end of said fuse being closed and the other 'end thereof being open at least during a circuit interrupting operation, means olf-a material capable of evolving an arc extinguishing gas when in proximity to an electric arc forming a narrow arc passage in said enclosure, meansbiased to draw an arc along said passage toward the open end of said fuse, fusible means connecting-said terminal means and arc drawing meansto normally prevent relative movement thereof, a exible shunt connecting said arc drawing means to the other of said holder contacts, and means venting-the closed end of said fuse to the open end thereof.

19. Ix a fuse, a tubular fuse holder of insulation material having contact means adjacent opposite ends thereof, a rell unit for said holder` and including a tubular enclosure having a terminal at one end thereof and adapted to'be supported in said holder adjacent one end thereof -with said terminal' electrically connected with ing a substantially annular vent passage substantially concentric with respect to said arc passage.

20. In a circuit interrupter, an enclosure having an open end, means in said enclosure forming a restricted arc passage communicating at one end thereof with' said open end of' said enclosure, means for striking an arc in said passage, auxil- Aiary passages in saidenclosure for ventingthe other end of said arc passage to said open end of said enclosurehat least inner wall portions of said arc passage being of a material capable of evolving an arc extinguishing gas whenheated, and partition means between said passages which ing-gas whenin proximity to an electric arc forming a narrow arc passage in said rell enclosure,

resilient means wholly supported on said unit for drawing an arc through said passage, fusible means connecting said'terminal means and arc drawing means to 'normally prevent relative a movement thereof, and shunt means electrically connecting said arc drawing means to the other of said holder contact means.

' HAROLD H". FAHNOE.

Jan- 5, 1942- c. A. NlcKLE ETAL 2,269,345

PERMANENT MAGNET Filed Jan. l2,V 1940 Nei i Att-farm@ 

